kaifu says one main reason for the rapid eel population decline could be global warming. he points out river banks covered in concrete may be another factor. and he suspects overfishing is also to blame. eels are a highly profitable fish. they are caught young and sold to farms in east asian countries. >> japanese eels caught not just in japan, but china, south korea and taiwan. in these countries, eel farming and fishing started growing dramatically since the 1970s. >> reporter: the red list does not automatically regulate or ban fishing. but kaifu believes that now is the time for nations in the region to cooperate on conservation and sustainable use of the endangered fish. >> the serious decline of such a largely important fish species may cause conflict among state quarters such as fishermen, fish farmers, dealers, restaurant owners, conservationists and scientists. conflicts may not occur not only among the country here but also the country in east asia. in order to solve the conflicts among quarters, information sharing is needed. the international -- is there but n